Millions of people suffer from progressive gastroesophageal reflux disease (GERD) which is characterized by frequent episodes of heartburn, typically on at least a daily basis. Without adequate treatment, GERD can cause erosion of the esophageal lining as the lower esophageal sphincter (LES), a segment of smooth muscle located at the junction of the stomach and the esophagus, gradually loses its ability to function as the barrier that prevents stomach acid reflux. Chronic GERD can also cause metaplasia to the inner lining of the esophagus where the normal squamous mucosa changes to columnar mucosa, also known as Barrett's esophagus. Barrett's esophagus can progress to esophageal cancer if left untreated.
Endoscopic treatment of Barrett's esophagus includes endoscopic mucosal resection (EMR). One method of performing EMR involves ablation of the mucosal surface by heating the surface until the surface layer is no longer viable. The dead tissue is then removed.
Treatment devices for performing EMR have been developed using bipolar ablation technology that includes extending a distal end of a probe to the target tissue and delivering energy to the tissue by either touching the distal end of the probe or the side of the probe against the tissue and supplying energy to the probe to ablate the tissue in contact with the probe. The probes may be provided on an inflatable balloon. The balloon must be inflated to a predetermined size to achieve contact with the diseased tissue for delivery of the appropriate amount of energy from the bipolar ablation device to ablate the diseased tissue. In order to determine the correct size and balloon pressure to achieve adequate ablation, a sizing balloon must first be introduced into the esophagus. The sizing balloon adds an extra step to the procedure when a balloon inflated probe is used for tissue ablation. In addition, the inflated balloon is positioned in front of the endoscope viewing window, preventing direct visualization of the target tissue and potentially leading to ablation of healthy tissue or incomplete ablation of diseased tissue.
Another potential drawback of the current ablation probes is that the size is limited in that the contact area available for one energy application is limited by the size of the accessory channel of the endoscope. Most of the current ablation probes have an outer diameter of either 7 French (Fr) or 10 Fr. In many patients, the area of the tissue needing treatment is larger than the size of the probe and multiple repositionings and applications of energy to the probe are needed to adequately ablate the diseased tissue.
What is needed in the art is an ablation treatment device that is simple to use, that minimizes the number of steps and time required for a treatment procedure, that is sized to fit in a standard accessory channel and then expand once the distal end of the device exits the accessory channel and that provides treatment under direct endoscopic visualization.